Coordinated heater and speed control for web drying machines



Feb. 26, 1963 w.- F. HUCK r 3,0 8

COORDINATED HEATER AND SPEED CONTROL FOR WEB DRYING MACHINES.

Filed Jan. 29. 1959 4 Sheets-Sheet 1 INVENTOR: WM. F. H UCK FATTORNEYFeb. 26, 1963 w. F. HUCK 3,078,587

COORDINATED i-iEATm AND SPEED CONTROL FOR WEB DRYING MACHINES Filed Jan.29. 1959 I 4 Sheets$heet 2 INVENTOR )A/M. HucK BY WW lax ATTORNEY Feb.26, 1963 w. F. HUCK 3,078,587

COORDINATED HEATER AND SPEED CONTROL FOR WEB DRYING MACHINES Filed Jan.29. 1959 4 Sheets-Sheet 3 INVENTOR WM. F. HUCK BY WW ORNEY Feb. 26, 1963w. F. HUCK 3,078,537

COORDINATED HEATER AND SPEED CONTROL FQR WEB DRYING MACHINES Filed Jan.29, 1959 4 Sheets-Sheet 4 IHEATERI I HEATER I SPEED CoNTRbL SPEEDADJUSTMENT 85 83 (I: "*R MACHINE lllllllll @15 WM. F. HUCK 5 INVENTOR:

United States Patent Cfilice 3,673,587 Patented Feb. 26, 1963 3,078,587COORDHNATED HEATER AND SPEED CQNTRGL FGR WEE DRYING MACHiNES William F.Huck, Forest Hills, N.Y., assignor, by mesne assignments, to William F.Huck, doing business as Huck Company, New York, NX.

Filed Jan. 29, 1959, Ser. No. 789,970 Qlaims. (Cl. 34-48) The presentinvention provides improvements in the automatic and coordinated controlof the relationship between the heating effect and the rate of Webtravel, in web processing machines such as printing presses or the like,or similar machines involving any kind of moistening and drying stageswhere heat is employed as the drying agent.

The invention is particularly applicable to machines and processesemployed in the graphic arts industries, where the web material isusually paper or analogous foils which are susceptible to differentialshrinkage 0r extension as a result of moistening and drying operations.For this reason, the following specification will be directedspecifically to such typical examples but without any intention therebyto limit the applicability of the principles of the invention to suchinstallations.

Presently known automatic heating control devices, which are used toregulate electrical heating effects, or heating and drying by hot air,oil or gas flames, or steam or hot water drums and the like, operate onthe principle of attempting to maintain a constant temperature, eitherdirectly on the web or in ovens surrounding the web. These controlsinvariably require continuous small fluctuations of the heat input abouta certain median value, in an attempt to maintain constant net heatingeffect on the web, even when the latter is moving at a constant speed.This hunting action is due to the inherent time delay in such controls,between the sensing of errors and their correction. The effect of thetime delay is less serious when the web speed is constant, but becomesmore so during periods of web speed change. Also, while such systems maywork well enough at slow processing speeds because the delay edectsaverage out over the relatively lengthy exposure time of a web region tothe heating effect, they introduce intolerable errors at high processingspeeds.

For example, that section of a web length subjected to more heat willshrink more than another section subjected to less heat, producing acorresponding variation in register accuracy. Tests have shown that twohundred inches of moist paper web subjected to a temperature variationof 35 Fahrenheit will vary in length approximately 0.0 1 inch (due tothe combined effects of thermal expansion and desiccation), whereas, inhigh quality printing work, a variation of 0.005 inch in web register isconsidered excessive.

It is accordingly a principal object of this invention to provide asimple and reliable heat input control that will automatically assurethe predetermined heating effect required for a selected web speed, andwill thereafter maintain this heating effect in a proper functionalrelation to the web speed, without fluctuations of any sort. Theinvention achieves this aim. by providing an arrangement such that themagnitude of heat input can be established for two or more values of webspeed within the range desired, as by experiment at these speeds, toestablish a correct functional relation which should be maintained.These values are set manually into an adjustable cam device having apreferably flexible surface, which therefore conforms to interpolatedvalues between the successive control values as already established.Where the cam is a rotary element, its angular position will becontrolled by the speed adjusting means of the web process machine, anda suitable follower riding on the cam surface will set the heat inputcontrol, be it electrical or of other type, to the desired correctposition for optimum heating effect at the particular speed of the web.Thus, the invention will provide correct heat control for each given Webspeed, even when the latter varies rather widely, as during startup andshut-down operations, and without the usual fluctuations which areinherently involved in the technique of sensing a temperature change inthe web, and only after such a change occurs, initiating a heatingvariation. Also, of course, since the invention provides a normallyconstant heating effect for a given web speed, the hunting variations ofconventional controls, which occur even at constant speed, will not beintroduced.

Briefly, then, the invention provides a control system for machinesprocessing webs and including the heating or drying thereof, such thatthe magnitude of the heat input effect is instantaneously varied underdirect control of the machine speed, or web travel speed, according to apredetermined arbitrary, empirical, or even calculated schedule defininga functional relationship which has been established as satisfactory;and this, apart from any direct control of the heating effect bytemperature sensing. Preferably, the control is exercised through themedium of a settable cam including a flexible cam surface, to providesmooth interpolation for values between those established directly bymeasurement or observation. A web temperature sensing safety or limitcontrol can, of course, be used as an auxiliary device to preventexcessive heating by shutting off the fuel or heat supply entirely.

Certain preferred embodiments of the invention will now be disclosed indetail, by way of example, and with reference to the appended drawings,in which:

FIGURE 1 is a schematic side elevational view of a typical web processmachine incorporating the invention, shown with the near side machineframe removed for clarity.

FIGURE 2 is a plan view of a preferred form of heatcontrol cam devicesuitable for control in accordance with the machine speed.

FIGURE 3 is a vertical sectional view, taken along the broken line 3-3of FIGURE 2.

FIGURE 4 is a fragmentary schematic view, similar to FIGURE 1, butshowing the invention applied to a different specific web processmachine.

FIGURE 5 is a schematic view showing the invention as applied to a webprocess machine utilizing fuel-fired web heating or drying.

Referring first to FIGURE 1 of the drawings, there is shown a typicalweb processing machine in which a web W, of paper, for example, unwindsfrom a supply roll H and then travels vertically upward into a webtension control device 12 which may be of the type shown in Huck Patent2,787,463 of April 2, 1957. Web W thereafter travels to the right overidler roller 13 and subsequently downward into the tinting bath 14 whichsaturates the web material with a tinting liquid. The excess moisture isremoved from the web by the action of squeegee rollers 15, 15a againstthe impression cylinder 16, after which the damp web travels upward intothe drying oven 17 where it is dried by radiant electric heaters 18. WebW, after emerging from oven 17, next comes into contact with coolingrollers 21 which are part of the Web tension control mechanism 25 theoperation of which is fully described in the pending patent application,Serial No. 677,143, filed August 8, 1958, now Patent No. 2,949,295. Thesaid application, filed in the name of the present inventor, is assignedto the owner of the present application, and provides a system forequalizing the web tension in web W before and after heating and coolingof the web.

The operations described above are then repeated by passing the tinted,dried and cooled web horizontally to the right along the bottom of themachine and then upward into a gumming unit, generally indicated byreference numeral 22, which applies an adhesive gum coating of uniformthickness to the web. The web then travels upward to a second dryingoven 17a and thereafter is brought into contact with cooling rollers 21aof tension control mechanism 20a, these parts being identical with thosealready described and having similar but unlettered reference numbers.Finally, the web exits to the right where it may undergo additionalprocessing, or be coiled for shipment.

The processing machine is driven by a motor 31 through belt drive 32 anda horizontal driveshaft 33 which runs along the top of the processingmachine as shown in FIGURE 1. Each unit of this machine is drivenindividually by vertical transmission shafts 34, 35, 36, 37 and 38. Thespeed of drive motor 31 is controlled by speed variator unit 40, a wellknown commercially available speed control device. Control unit 40 has ashaft extension 41 which changes its position as the variator calls forweb speed variations. The heating control mechanism, generally indicatedby numeral 42, is carried on this shaft extension.

In a typical constructed embodiment of the invention, the power input tocontrol unit 40 was of the three-wire, 230 volt, 60 cycle, three-phasealternating current type. Control unit 40 also contains a rectifierdevice which converts this input power to direct current to drive motor31, in a typical variable speed press drive. However, the principles ofthe invention are applicable to any other form of electrical powersupply, as will be understood by those skilled in the art.

'Heating control unit 42 is indicated only schematically in FIGURE 1,and for a detailed description thereof, reference will now be made toFIGURES 2 and 3 of the drawings. As there shown, the device consistsessen tially of a variable contour cam whose contour is formed byflexible strip 51, preferablyof polished metal or the like, which wrapsabout pins 52 and is secured at its ends to pins 53 by means of cotterpins 54. Pins 53, as best shown in FIGURE 3, may be secured in properradial position within their range by means of a clamping nut 53a andwasher 53b. Each of the other pins 52 is precisely adjustable, in theradial direction, by means of a threaded screw 57 journalled in a block57a secured as by welding to the disc 56, and engaging the threads ofacorresponding pin-carrying head 58. The arrangement permits'the operatorto select one or more of the cam points at will, as dictated byknowledge or experiment, and then to establish the other cam-definingpoints to obtain satisfactory operation for other values of web speed.

A cam roller 61 is held in continuous contact against flexible strip 51by spring 62. Follower arm 63 pivots about shaft 64 and has a gearsector 65 attached to its opposite end. The gear sector meshes withpinion 66 on the output shaft element 67 which has an extension 68carrying the wiper arm 68a of a heating control rheostat 69. Shaftextension 41 constitutes the input element of the over-all heatingcontrol mechanism, and thus controls the position of the output shaftelement 67 to modify or alter (and thus act as a regulator for) theapplication of heat to the web as the web speed changes.

The slotted disc 56 is positioned on input shaft extension 41 as bymeans of set screws 70 in hub 71, so that the disc rotates identicallywith the input shaft 41, which, as has been stated, operates like aspeedometer spindle;

that is, the angle through which the shaft moves is proportional to thechange in the operating speed of its associated device. Frame pieces 72and 73, located at right angles to the shaft 41, are supported by hub 74fixedly secured to a stationary plate 75, in turn secured to speedvariator control unit 40 as seen in FIGURE 3. In operation with awebprocessing machine in which flexible materials such as paper, cloth,felt and the like are moistened by tinting, water-marking, gumming,printing and so on, and subsequently dried by heating, the input shaft41 is actually an extension of the drive motor control rheostat which isset, usually manually, to establish the desired speed of the travelingweb. Rheostat 69, on the extension 68 of output shaft 67, is lo cated inthe heating circuit, or heating control circuit, of the drying unit.Since the variable cam unit is driven by shaft 41, it follows thatrheostat 69 will be varied in accordance with any change in the webtravel speed, to an extent regulated by the shape of the cam. Hence, achange in web speed is immediately reflected as a modulation in the heatinput to the web, without any delay of the kind involved in systemswhich vary the heat control only in response to an actual change in thetemperature of the web.

FIGURE 4 of the drawings is similar to FIGURE 1, but illustrates thecontrol as applied to a multiple impression printing press, the tintingunit 14, 15, 16 having been replaced by an imprinting unit 76 whichplaces printed pat-terns on one side of web W, and gumming unit 22 hasbeen replaced by a second imprinting unit 77, which prints patterns onthe other side of the web. Similar arrangements can be used with otherforms of perfecting or multi-color presses and analogous machinesrequiring heating or drying facilities.

From what has been said, it will be obvious to those skilled in the artthat the invention does not depend upon the particular type of speedregulator which is employed, so long as it provides an output shaft, orother movable element, whose position is uniquely related to the webtravel speed. Thus, the control shaft maybe a manual speed control, orit may be a mere speed indicating shaft, or it may be a part of anautomatic speed regulating system. In any case, accurate control of theweb heating power input will depend only upon the accuracy with whichthe'operator in charge of the machine adjusts the variable cam, whichcan best be done by trial and error with a given machine set-up,material, process and like parameters.

FIGURE 5 of the drawings illustrates in schematic form a variation ofthe invention which is particularly applicable to machines which employother than electrical heating power, and in which, therefore, thecontrols for the heat input are likely to be near the point of heatapplication and hence remote from the motor speed control. Also, thecontrols for such systems may well be multiple valves or other multiplecontrols.

FIGURE 5 therefore illustrates a servo or follow-up control systembetween the speed variator shaft and the controlled device or devices,here exemplified as a fuel valve 80 in a gas line 81 supplying a flamedrying unit 82 arranged to dry a web again denoted W. The web drivemotor is indicated at 83, connected by chain or like drive means 84 tothe main shaft 85 of the web processing machine. A speed control formotor 83 is indicated as a rheostat 86 electrically in series with thefield winding of the motor, but it will be understood that equivalentdifferent systems can be employed. In any case, the actual speedadjustment is made by a shaft 87 under suitable manual or automaticcontrol, said shaft being connected to the shaft 88 of rheostat 86 inany convenient manner, herein by a chain 89. Remote control of the heatcontrol unit 42, which is the same as in FIG- URES l, 2 and 3, isaccomplished by a remote control system here exemplified as a servometer90 acting as a transmitter, and a similar unit 91 acting as a receiver.As well known, such devices are capable of reproducing mechanicalmotions to good accuracy over wire lines, here shown as three conductors92.

For good accuracy and sensitivity, I have shown shaft 88 as connected totransmitter 90 through step-up gearing 93, and receiver 91 connected tounit 42 by equivalent step-down gearing 94; the servo system may ifdesired be of the alternating current Selsyn type, but many equivalentremote control systems can also be utilized. Where more than one valveor like fuel control device must be adjusted, a single transmitter 90may transmit control signals to several receivers, each connected to avalve.

It sometimes happens that a particular control cam unit setting can beused for several different processes, with a change in the effectthereof which is proportional throughout the control range; for example,where the only process change is a change in the basic weight of the webmaterial. In such cases, it is unnecessary to readjust the entire camstrip 5-1, because the necessary correction may be made merely by properphasing of the output shaft of the control unit. As shown in FIGURE 5,such may be accomplished by altering the positions of two adjacent gearsas at 93 or 94, or by changing the position of fol-lower arm 63 relativeto the damper shaft of the valve 80.

FIGURE 5 also illustrates a completely independent safety shut-ofl? forthe fuel line, in case of dangerously excessive temperatures or fire.This includes a shutoff valve 95 operated under control of athermocouple-type thermometer 96 of known kind arranged to sense thetemperature of web W and to complete a control circuit, shown onlydiagrammatically, when the web temperature rises too high, or beyond therange of the heat control.

The foregoing description has been given in considerable detail toenable those skilled in the art to make and practice the invention, butit is to be understood that the basic concept of the invention can becarried out by other arrangements. Basically, the invention depends uponthe discovery that drying by heating, of webs, and especially at highproduction speeds, cannot satisfactorily be controlled merely bymaintaining constant the temperature of the web, as is done with knowncont-rol systems. As a rule, a given web temperature does not result inthe same drying effects at different speeds, in cases where drying timeis a factor. When these previous systems are employed, a manualreadjustment of the set temperature is necessary whenever web speed isbeing changed. The invention also depends upon the realization thatproper drying and improved operation can be attained by controlling thenet heating effect (not the web temperature) immedimately in response toa change in Web speed, and to a defined degree, not by oscillating theheating effect about a desired constant level. These concepts can, ofcourse, be implemented in various ways, and all such are intended to beincluded within the spirit of my invention, if they fall within thescope of the appended claims.

What is claimed is:

1. In a Web processing machine of the type including, in combination,web conveying means, speed control means for adjusting the speed of saidconveying means and thereby the speed of web travel, means forsubjecting the Web to a treatment increasing the fluid carried thereby,and drying means and a regulator therefor for applying heat to thetreated web whereby to decrease its fluid content subsequent to saidtreatment, the improvement which comprises means cont-rolled solely inresponse to the adjustment of said speed control means for modifying theapplication of heat to the web in accordance with a predetermined directfunctional relationship to said adjustment; said modifying meansincluding a variable contour cam type motion-transmitting mechanismhaving an input element connected to said speed control means and anoutput element to said regulator for the drying means to control theapplication of heat to said web.

2. The combination according to claim 1, in which said drying meanscomprises electrical heating elements, and in which the modifying meanscomprises a rheostat in circuit with said electrical heating elements,said 'rheostat being connected for control by the output element of saidmotion-transmitting mechanism.

3. The combination according to claim 1, in which said drying meanscomprises gas-fired heating means, and in which said modifying meanscomprises a gasflow control valve connected for control by the outputelement of said motion-transmitting mechanism.

4. The combination of claim 1, in which said mechanism comprises aflexible cam strip and means for holding said strip in any desiredconfiguration at a selected number of points along its length.

5. The combination of claim 4, in Which said cam unit also comprises asupport plate mounted to rotate in response to changes in the adjustmentof said speed control means, and in which said cam strip is secured tosaid plate for rotation therewith; and a cam follower biased againstsaid strip and connected to said drying means.

References Cited in the file of this patent UNITED STATES PATENTS1,023,316 Hurwitz Apr. 16, 1912 2,409,431 Hess Oct. 15, 1946 2,420,399New May 13, 1947 2,445,443 Long July 20, 1948 FOREIGN PATENTS 580,627Germany July 13, 1933

1. IN A WEB PROCESSING MACHINE OF THE TYPE INCLUDING, IN COMBINATION,WEB CONVEYING MEANS, SPEED CONTROL MEANS FOR ADJUSTING THE SPEED OF SAIDCONVEYING MEANS AND THEREBY THE SPEED OF WEB TRAVEL, MEANS FORSUBJECTING THE WEB TO A TREATMENT INCREASING THE FLUID CARRIED THEREBY,AND DRYING MEANS AND A REGULATOR THEREFOR FOR APPLYING HEAT TO THETREATED WEB WHEREBY TO DECREASE ITS FLUID CONTENT SUBSQUENT TO SAIDTREATMENT, THE IMPROVEMENT WHICH COMPRISES MEANS CONTROLLED SOLELY INRESPONSE TO THE ADJUSTMENT OF SAID SPEED CONTROL MEANS FOR MODIFYING THEAPPLICATION OF HEAT TO THE WEB IN ACCORDANCE WITH A PREDETERMINED DIRECTFUNCTIONAL RELATIONSHIP TO SAID ADJUSTMENT; SAID MODIFYING MEANSINCLUDING A VARIABLE CONTOUR CAM TYPE MOTION-TRANSMITTING MECHAN-